Automatic machine for lapping of marble slabs and other similar stones



March 27, 1962 B. DE ZORDO 3,026,653

AUTOMATIC MACHINE FOR LAPPING OF MARBLE SLABS AND OTHER SIMILAR STONES Filed 001;. so, 1959 Y 5 Sheets-Sheet 1 B. DE ZORDO AUTOMATIC MACHINE FOR LAPPING OF MARBLE SLABS AND OTHER slMILAR STONES March 27, 1962 s sheets-sheet 2 Filed Oct. 60, 1959 INVENTOR BY 6 M United States Patent 3,026,653 AUTQMATHI MACHINE FOR LAPPKNG F MAR- BLE SLABS AND OTHER SIMHLAR STONES Battista De Zordo, Bergamo, Itaiy lug. A. Giambrocono, Via Durini 4, Milan, Italy) Filed Oct. 30, 195?, Ser. No. 849,897 Claims priority, application Italy Nov. 3, 1958 1 Claim. (Cl. 51*56) The present invention relates to an automatic machine for lapping marble slabs and similar stones.

The main object of the present invention is to provide an automatic machine for lapping or bufiing marble slabs or other similar stones according to mutually parallel and perpendicular directions and according to a predetermined program and this in a fully automatic manner after final set-up the machine.

According to the invention not only a considerable saving in labour is attained, but also lapping and bufiing of said slabs is made possible in a continuous and even manner.

According to the invention, the machine is of the type comprising a first carriage suitable for being displaced by motor means in a first direction, a second carriage slidably mounted on said first carriage and connected to motor means suitable for moving it in a second direction perpendicular to said first direction, said second carriage being connected to a known type abrasive machine, characterized in that said first carriage is connected to a motion distributing and reversing member for the respective motor means, said second carriage being connected to a further motion distributing and reversing member for the respective motor means and by the fact that a shaft is provided parallel to said first direction connected to the machine casing and provided with means to act on said first motion distributing member, and a second shaft is provided parallel to said second direction, associated with said first carriage, and provided with means to act with said second motion distributing and reversing member.

The above-mentioned and other features as well as the objects and advantages of the invention will clearly result from following description of a preferred embodiment diagrammatically illustrated in the attached drawing, in which:

FIG. 1 is a perspective and only partial view of the machine according to the invention;

FIGS. 2 and 3 show two details;

FIGS. 4 and 5 diagrammatically illustrate the possible paths of movement of the abrasive tools;

FIG. 6 shows an electric connection diagram;

FIG. 7 is a perspective detailed view of the distributingreversiug member for the electric motors controlling the two aforementioned carriages.

The machine, according to the invention, is of the type comprising a first carriage 10 which is slidably mounted along tracks 11 of which only one is shown in the drawing and is associated, at one of its ends 10a, with an electric motor 12. The latter by means of a reduction gear, not shown, controls a toothed pinion, also not shown, with a meshing rack 13 provided on track 11. The carriage 10 provided with rollers 14, may thus be displaced according to the FAFB direction arrows. The motor 12 is capable of rotating in two directions as Will better appear hereinafter. By 210 a second carriage is indicated movable in the directions of arrows FCFD, which are perpendicular to tracks 11. By 214, 212, 211, 213 are indicated elements corresponding to'14, 12, 11, 13 already described in relation to the first carriage.

By 30a lapping equipment of any known type and associated with carriage 210 has been indicated, which is obviously controlled by motor means independent from versing-distributing member 240 similar to 4d.

the ones 212 which control the reciprocating motion of carriage 210. The abrasive tools 30a and equipment 30 may therefore, act on a slab 31 located on a stationary plane 32. Carriage it} is associated to a distributing-inversion member 40 of the motion of motor 12: said member 49 comprises a commutator lever 41 pivoted in 42 and having a preferably fork shaped arm 41a and a suitably Shaped arm 41b. Parallel to track 11 a shaft 50 which is rotatably mounted on the machine casing is provided and it presents at one of its ends a four-lobed cam 51. A roller 52 is urged in an elastic manner by means of any known device between said lobes and therefore may firmly position shaft 50 correspondingly to the number of lobes. Along shaft Sit a plurality of projections 7% are provided on sleeves 71 which may be mounted, for example, as indicated in FIG. 2, on shaft 50. That is, said sleeves 71 may be formed by two mutually hinged branches 71a and 71b and friction connectable to shaft 56 by means of a screw 71c, preferably shaft 50 presents a longitudinal slot 50a along which sleeve 71 may slide.

At the'ends of shaft 59, two projection devices are mounted, each one having four projections 9t}, preferably longitudinally offset and at 90 apart. One, of said devices being fixed and the other, preferably adjustably mounted on shaft 50. Parts 91a, 91b, 91c correspond to parts 71a, 71b, 710 relating to FIG. 2. Projections 99 act only on arm 41b of lever 41 and projections 70 act only on arm 41a of fork shaped lever 41. Naturally, it is not possible that projections 7% act on arm 41b this being obtained by suitably proportioning the length of the projections. Projections 7G by acting on arm 41a, allow commutation of electric motor feed 12 and 212 and therefore will be designated as commutating projections, while projections 90 act on arm 41!) of lever 41 thus reversing rotation of motor 12 and will thus hereinafter be called reversing projections or stop projections.

Referring now to FIG. 1 it is noted that a shaft 25% is parallelly mounted to the arrows direction FC-FD and rotatably mounted on a couple of brackets A, fixed on carriage 10 and thus movable with the latter according to the arrows direction FAFB. At said shaft 25d cornmutating projections and reversing stop projections similar to the ones specified above are provided. Carriage 210 is also associated to a motion re- Thus the parts similar to the ones previously described have been marked with the same reference numbers preceded by number 2.

According to a feature of the invention a coupling device is provided between shafts 5t) and 250 so that rotation of a shaft permits the rotation of the other. Said device consists of two props 8t 2% respectively connected to shafts 50 and 25b and of a rod 282 fitted to carriage 216; said rod 282 has a transversal extension 283 at its end suitable for positively rotating the prop 8t when carriage 210 is displaced in the FD arrow direction and an extension 284 suitable for positively rotating prop 28% when carriage 210 is displaced in the FB arrow direction. Having described in its essential elements the machine structure according to the invention its operation may be schematized as follows.

By referring to diagram of FIG. 4 in the first instance the travel appears identified by section a. At the stop the reversing projection iii intervenes whereby motor 12 stops and automatically motor 212 starts determining travel b until a porjection 270 acts on member 2% interrupting feeding of motor 212 and allowing feeding of motor 12; the latter displaces the carriage according to the PB direction namely it allows the lapping machine to travel according to path 0. At the stop (in the PB arrow direction) the reversing projection 90 intervenes and stops motor 12 and allows at the same time feeding of motor 212 and thus the path according to section d and so on automatically for the e, f, g, h, i, l, m sections.

At the end of the m path the reversing projection 290 intervenes whereby lever 241 is in an angularly displaced position, the same occurring to lever 41. The cycle identified by the interrupted lines is thus newly repeated. At the end of this second cycle rod 282 intervenes and rotates shafts 250 and 50 through an angle of 90 setting the machine for another automatic travel for example the one identified by FIG. and this obviously according to the position and number of projections 270 and 70. Since four angular displacements of shafts 50, 250 are foreseen, the third and fourth cycle might be different from the ones in FIGS. 4 and 5 always with the aim of working the slab according to different paths and working slab 31 according to a plurality of paths which are repeated automatically and cyclically.

Referring now to diagram of FIG. 6 in which electrical connections of motors 12 and 212 (three-phase) are indicated, as well as FIG. 7 which shows in perspective and partial view member 40. Lever 41 is connected to an insulating part 37 in which are buried three rings 60a, 60b, 600, only one of which 66a is seen in FIG. 6. As appears from the drawing, each ring 60a, 63b, 69c presents a contact projection 600'. In addition, said insulating block is combined with a slab 62 having a nosing 63 which operation of will be hereinafter described. Three thin columns 64, 65, 66 are provided; of which the 64 one bears three brushes 64a; the 65 one bears three brushes 65a; the 66 one bears three brushes 66a. Said brushes are partially seen in FIG. 7. The three 64a brushes are connected to a branch A of the E feedline while brushes 65a, and 66a are connected by a threewire cable 67 to which a cable 63 is branched thus feeding motor 12. Cable 67 connects said brushes in such a way that the motor turns in one direction or in the the opposite direction according to the feed from 64a 66a brushes or from 64a65a brushes. A transformer 69 may feed under control of switch 8 an electromagnetic switch 7 which allows feeding of 64a brushes. Said electromagnetic switch 7 additionally controls a switch 08 which controls feeding of a second electromagnetic switch 07 similar to switch 7. In series to the feeding conductor of the electromagnetic switch 7 two switches are provided 5, 5a, the opening of which is controlled by a nosing 63 of plate 62. The latter has two positioning recesses 62a, 621;, corresponding to the contact of projections 60d with, brushes 65a, 66a. Corresponding to said recesses 62a, 621) a pressure small roller 630 is inserted with elastic stress in such a way as to firmly position the plate 62. Projections 70 cause temporary opening of switch 5 (5a) while the pressure roller 63c returns plate 62 and then lever 41 in the position preceding the arm 41a impact with a projection 70. As far as the feeding circuit of motor 212 is concerned, it has to be noted that the same elements as for the previous circuit are applicable which have been marked with the same reference numbers preceded by numeral 0.

It clearly appears that the reversal of rotation of motor 12 (212) is obtained by passing contacts 69d from brushes a to 660: and vice-versa, this occurs due to reverse projections 90. On the contrary, to pass from feeding of motor 12 to 212 it is sufiicient that the nosing 63 acts on switch 5 (5a); this occurs due to commutating projections 70. Obviously, the same occurs as far as motor 212 is concerned.

In fact, for example, as soon as feeding of electromagnetic switch 7 is interrupted, switch 08' is closed and thus electromagnetic switch 07 is fed which opens switch 8 and thus it does not allow feeding of electromagnetic switch 7 even if one of switches 5 is then closed.

It is apparent however, that simultaneous feeding of motors 12 (212) is not possible in any way and a correct operation of the machine is thus ensured.

Iclaim:

An automatic machine for lapping of marble slabs and the like comprising a first carriage mounted to be displaced by first motor means in a first direction, a second carriage mounted sliding on said first carriage, and associated to second motor means able to displace it in a second direction perpendicular to said first direction, said second carriage being associated to an abrasive machine of known type, the said first carriage being connected to a motion distributing-reversing member of the said first motor means, said second carriage being combined with a further motion distributing-reversing member of the said second motor means, a first shaft being provided parallel to said first direction connected to the machine casing and provided with means to act correspondingly to said motion distributing-first member and a second shaft being provided parallel to said second direction, connected to said first carriage and provided with means able to act correspondingly the said motion distributing-reversing second member, said first and second shaft being kinematically connected to one another so as that the rotation of one causes the rotation of the other for a preestablished rotation angle due to the displacement of said second carriage.

References Cited in the file of this patent UNITED STATES PATENTS 1,038,404 MarOni Sept. 10, l9l2 1,773,388 Canning Aug. 19, 1930 2,075,369 Stetler Mar. 30, 1937 2,326,264 Stetler Aug. 10, 1943 

